Relay operated temperature responsive control system



Dec. 30, 1952 w, SM|TH 2,623,699

RELAY OPERATED TEMPERATURE RESPONSIVE CONTROL SYSTEM Filed July 1, 1949IN V EN TOR.

Patented Dec. 30, 1952 OFFICE RELAY OPERATED TEMPERATURE RESPON- SIVECONTROL SYSTEM William M. Smith, Glen Ellyn, IlL, assignor to VaporHeating Corporation, Chicago, 111., a corporation of DelawareApplication July 1, 1949, Serial No. 102,563

Claims.

This invention relates to new and useful improvements in a temperatureresponsive control system.

A principal object of the invention is to pro. vide a thermostaticallycontrolled circuit suitable for automatically eiiecting modulatedoperation of means controlling the heating of a space so that thetemperature thereof will be maintained substantially constant.

Another object of the invention is to provide a thermostaticallycontrolled circuit of the above character which will be suitable forintermittently energizing a solenoid operated ratchet motor formodulating the position of a damper in an air delivery duct; thenecessary intermittent or cycling action of the circuit being obtainedthrough the use of a delayed action relay.

Other and further objects and advantages of my invention will beapparent from the foilowing description when considered in connectionwith the accompanying drawings in which: Fig. 1 is a diagrammatic viewof a means for heating or cooling an enclosed space, together with acontrol circuit for modulating the position of a damper for controllingthe supply of heated and/or cooled air to the said space.

Fig. 2 is an elevational view, partly in cross section, showing asolenoid operated ratchet mo tor employed to adjust the position of adamper.

Fig. 3 is an end elevational view of the solenoid operated ratchet motorshown in Fig. 2.

Referring to Fig. l of the drawings, the numeral I0 designates generallya conduit for delivering air into a space whose temperature is beingcontrolled. The said conduit is provided with a partition I I whichdivides it into two separate passages I2 and I3. The passage I2communicates with a heating means, not shown, while. the passage I3communicates with a cooling means. For purposes of illustration, thepassage I2. is shown as having a heating element I4 disposed thereinwhile the passage I3 is shown as having a cooling element I5. However,the cooling, means can be omitted, when unheated air is sufficientlycool to provide a blended air stream of suitable temperature. A damperI6 i located within the conduit II) to control the amount of heated andunheated air entering the space whose temperature is being controlled.The damper l6 may be of any suitable construction. It. lsshown herein,for purpose of illustration, as comprising a sheet-like member formed ina curved plane and mounted on an arm I! which is rlgidly fixed onadriving shaft Ill. The damper the controlled space.

I6 is movable with the shaft, and in one extreme position, only heatedair can be introduced into the enclosed space, while in another extremeposition only unheated air can be introduced into the space. However,whenever the said damper is in any intermediate position, both heatedand unheated air are admitted into the space in proportions determinedby the position of the damper.

The position of thedarnper is adjusted by intermittent movements bymeans or a solenoid operated ratchet motor, indicated generally by thenumeral It. The movements of said motor are controlled in relation tothe temperature of If the temperature of the space is at a desired pointthe control motor 59 will remain inactive. However, if there should be aslight change in the temperature of the space, either up or down, thecontrol motor :9 will be operated to efiect an adjustment of the damperI6, in one direction or another, so as to increase or reduce the supplyof heat to the space, as may be required to balance the control system.

The. control circuit for operating the motor I9 and therefore modulatingthe position of the damper I8, comprises a thermostat 2| arranged in thespace being controlled so as to be influenced in its operation by thetemperature of the said space, relays 22 and 2.3, delayed action relay24, solenoids 34 and 35 of motor I9 arranged in opposed relation, andconductors for connecting the above elements in a manner hereinafterdescribed.

The thermostat 2| is preferably of the mercury column type and isconstructed so as to function at predetermined temperatures. Thethermostat is shown as having spaced contacts 2l28 which define thelower and upper limits of a. temperature range; the lower limit, forpurpose of illustration, may be 72 and the upper limit as represented bycontact 28 may be 74. The third contact 28 is placed at any suitablelocation so as to be engaged by the mercury column of the thermostat 2Iduring the normal operation of the control system.

The solenoid operated ratchet motor I9 may be of any approvedconstruction and may take the form illustrated in Figs. 2 and 3. Thesaid motor includes a substantially U-shaped bracket 30 in theupstanding legs 3!, 3| of which journaled the driving shaft l8. Fixed onthe shaft I8 for rotation therewith are a pair of ratchet wheels. 32 and33 with the teeth of one arranged in a direction'opposite the teeth of 3the other so that reversal in direction of rotation of the shaft l8 maybe efiected.

Arranged in opposed relation and cooperating with the ratchet wheels 32and 33 are solenoids 34 and 35 respectively. Since, the said solenoidsare identical in structure a description of one will be deemedsufficient. The solenoid 34 includes a coil 35 having a core opening 31in which an armature 38 is received for sliding movement. The armature38 is provided with an extension 39 which carries near the end thecircuit to the solenoid 35. Engagement bethereof a tooth 40 adapted forengagement with a cooperating ratchet wheel 32. As will be clearly seenin Fig. 2, the tooth 40 is provided with an inclined surface 4| and isbiased by a spring 42 so that the tooth 40 will operatively engage atooth of the ratchet wheel 32 when moving in a direction towards theleft, as viewed in Fig. 2, and will slide under a tooth of the ratchetwheel when moving in the opposite direction or towards the right. Atension spring 43 carried on an upstanding lug 64 is connected to theend of the armature extension 39 and normally serves to maintain thearmature in the position shown in Fig. 2 which corresponds to adeenergized condition of the coil 35. The coil 35 is provided with ashoulder 46 around the core opening 37 which serves as a'stop to limitthe travel of the armature 38 when moving to the right, and is providedwith a pin 6'! at the opposite end of the core opening to limit thetravel of the armature in the opposite direction. Suitable frictionmeans, here in the form of a split resilient ring 48 is provided betweenthe hub of each of the ratchet wheels and the upstanding leg 3| so as toprevent free rotation of the shaft l8 and inadverent displacement of thedamper I5. I

The manner in which movement of the damper I 5 may be effected will beapparent from the following description of the specific circuits whichmay be in control during the operation of the system. Assuming that thedamper It as shown in Fig. 1 is in a position to deliver equal amountsof heated and unheated air to the enclosed space and that the mercurycolumn in thermostat 2| stands below the contact 2'! which represents atemperature, in the space controlled, below the lower limit of thedesired heat range, and indicates a requirement for heat in the saidspace. The manual closing of switch A establishes an energizing circuitthrough the coil of relay 22. This circuit leads from positive line 5|)through resistor 49, coil of relay 22,

conductor 5|, thermostat contact 25, resistor r 52, and thence throughconductor 53 to negative line 6|. The energlzation of the relay 22causes the armature 52 thereof to move downwardly establishing contactbetween the points 54, 54 and contact bar 55, and points 51, 5'! andcontact bar 58, thus closing an energizing circuit to the coil of thedelayed action relay 2d. This coil energizing circuit leads from thepositive line 5|] through contacts 51, 51, contact bar 58, throughconductors 52 and 65, contacts 63, 63, contact bar 64. of relay 24,through the coil of relay 24 and thence through conducto B5 to negativeline 6|.

Energization of the relay 22 effects engagement of the contacts 58, 68with contact bar 59 establishing an energizing circuit through solenoid35 which imparts an operating movement to its associated armature andeifects through the movement of the ratchet wheel 33 a rotation of shaftIt in a direction to increase tween'the contacts 63, 53 and contact bar64 is again effected, and the energizing circuit through the coil ofsolenoid 24 is thus reestablished causing the armature 52 to movedownwardly to again effect engagement between ithe contacts 58, 68 andcontact bar 69. Again,

after a delayed interval of thirty (30) seconds, solenoid 24 loses itsresidual energy and the armature 51 moves to non-energized positioneffe'cting a reestablishment of the energizing circuit through solenoid35 imparting an operating movement to its armature and rotating theshaft |8'as hereinbefore described. Thus, in operation the solenoid 35'is intermittently "energized and the armature thereof impartscorresponding impulses to the ratchet wheel 32. Movement of the ratchetwheel effects through the shaft l8 a corresponding movement of thedamper It in a direction to increase the amount of heating air deliveredinto the space. It will be apparent that the motor energizingcircuit ismaintained only momentarily and consequently the damper will be adjustedby a series of intermittent movements until the proportionsof heated andcooled air passing through the duct iii are such as to increase thetemperature of the space and thereby cause the mercury'column of thethermostat 2| to rise to a position advancing toward contact 2! of thethermostat; The above described cycling action will continue until theratchet motor |9 has beenoperated sufliciently so as to adjust thedamper Hi to a position to maintain a desired temperature within thespace.

Assuming now that the heating requirements for the space have beensatisfied and; that'the mercury column of thermostat 2| has risen to apoint between contacts 2? and 28 thereof. In this condition, the currentfrom positive line 5:] following the path of least resistance bypassesthe coil of relay 22 and follows through resistance 49, conductor i3,contact 27, through the mercury column of the thermostat, throughcontact 26, resistance 52, through conductor 53 and thence to negativeline 6|. Thus, the relay 22 is by-passed and is not energized andconsequently solenoid 35 remains inactive and the position of the damper|5 remains unchanged. Assuming now that the mercury column in thermostat2| has risen to a point above contact 28 which represents a conditionabove the tem-' perature range desired in thespace. As will be apparentby tracing the circuit, the relay 23 normally is energized with itsarmature in the po'sif tion as shown in Fig. 1, that is, with thecontacts l6, l6 disengaged from the contact bar 11, and contacts l8, l8disengaged from contact bar It. The energizing circuit for the coil ofrelay 23 leads from positive line 5|! through resistance 8|, conductor82, through relay 23, resistance'52, through conductor 53, and thence tonegative line 6|. When however, the mercury column has risen to orbeyond contact 28 the coil of relay 23 is by-passed, the current passingfrom positive line 50, through resistance 8|, conductor 82, contact 28,through the mercury column of thermostat 2 I, through contact 26,resistance 52, through conductor 53, and thence to negative line 6|. Therelay 23 is thus de-energized and the armature is caused to moveupwardly efiecting enagement of the contacts l6, 76 with contact bar 11,and contacts 18, 78 with contact bar 19. It will be apparent that uponengagement of contacts 18, 16 with contact bar 19, an energizing circuitthrough relay 24 is established, the energizing circuit leading frompositive line 50, through conductor 83, contacts 78, 18, contact bar 19,conductor 65, contacts 63, 63, contact bar 64, through the coil of relay24, through conductor 66 and then to negative line 6!. This energizationof the relay 24 effects a downward movement of the associated armature61 effecting engagement of contacts 68, 68 with contact bar 69 andestablishing an energizing circuit through the solenoid 34. Theenergizing circuit leads from positive line 50 through conductor 86,contacts 76, 76 and contact bar 77, through the coil of solenoid 34,conductor 87, conductor H, through contacts 68, 68 and contact bar 69,through conductor 12 and thence into negative line 6|. Similarly, as inthe case of solenoid 35, the energization of the solenoid 34 imparts anoperating movement to its armature which causes the ratchet wheel 32 toadvance one tooth. The operating movement however, is in a reverse direction so that the shaft l8 correspondingly imparts a reverse movementto the damper l6 in a direction to increase the delivery of cooled airand to decrease the delivery of heated air to the space. Similarly, ashereinbefore described with respect to the operation of solenoid 35, therelay 24 after thirty seconds loses its residual energy releasing thearmature 61 so that it moves upwardly, effecting disengagement of thecontact bar 69 with the contacts 68, 68 thereby opening the circuit tosolenoid 34. The circuit through the solenoid 34 is again reestablishedimparting an operating movement to the damper I6. The same cyclingaction continues until the mercury column in thermostat 2| has droppedbelow contact 28.

It will be apparent that I have provided simplified automatic means foradjusting a control damper for proportionately varying the amount ofheated and unheated air, the necessary cycling or intermittent openingand closing of the circuit being accomplished through the use of asolenoid operated ratchet motor in circuit with a delayed action relay.

I claim:

1. The combination with a means for altering the temperature of anenclosed space including a valve movable to different positions to varythe efiectiveness of said temperature altering means, of mechanism forimparting adjusting movements to said valve including a first solenoidfor activating said mechanism in one direction, a first relay forpartially closing an energizing circuit through said first solenoid, asecond solenoid for activating said mechanism in the opposite direction,a second relay for partially closing an energizing circuit through saidsecond solenoid, a third relay cooperating with said first and secondrelays and adapted, when energized, to selectively close one of saidpartially closed circuits to energize one of said solenoids, alternativeenergizing circuits connected through said first and second relays forenergizing said third relay, and electrically energized means connectedin the energizing circuit of said third relay for maintaining itenergized for a predetermined time period.

2. The combination defined in claim 1 characterized in that themechanism activated by the first and second solenoids is a reversibleratchet motor and in that the said means for maintaining the third relayenergized is effective to automatically de-energize the same at the endof said predetermined time period.

3. The combination of claim 2 characterized by the provision of athermostat responsive to the temperature of the enclosed space andhaving spaced contacts defining the lower and upper limits of apredetermined temperature range, one contact being connected in shuntwith the winding of the first relay and the other contact beingconnected in shunt with the winding of the second relay.

4. The combination of claim 3 characterized in that the electricallyenergized means for maintaining the third relay energized for apredetermined time period is a condenser connected in shunt relationwith the winding of said third relay.

5. The combination of claim 4 characterized in that the third relay isprovided with a deenergized closed contact and in that said alternativecircuits for energizing said third relay are selectively closed by saidfirst and second relays in cooperation with said de-energized closedcontact of the third relay.

WILLIAM M. SMITH.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,618,828 Jones Feb. 22, 19272,300,537 Davis Nov. 3, 1942 2,366,500 Eastin Jan. 2, 1945 2,367,741Smith Jan. 23, 1945 2,382,073 Lehane et al. Aug. 14, 1945

